Add the weak-intrinsics feature #526
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danakj
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May 19, 2023
When enabled, the weak-intrinsics feature will cause all intrinsics functions to be marked with weak linkage (i.e. `#[linkage = "weak"]) so that they can be replaced at link time by a stronger symbol. This can be set to use C++ intrinsics from the compiler-rt library, as it will avoid Rust's implementation replacing the compiler-rt implementation as long as the compiler-rt symbols are linked as strong symbols. Typically this requires the compiler-rt library to be explicitly specified in the link command. Addresses rust-lang#525. Without weak-intrinsics, from nm: ``` 00000000 W __aeabi_memclr8 // Is explicitly weak 00000000 T __udivsi3 // Is not. ``` With weak-intrinsics, from nm: ``` 00000000 W __aeabi_memclr8 // Is explicitly weak 00000000 W __udivsi3 // Is weak due to weak-intrinsics ```
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Thanks! If this works well, we may even enable it by default in the future. |
Amanieu
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Jun 23, 2023
This was added in rust-lang/compiler-builtins#526 to force all compiler-builtins intrinsics to use weak linkage.
matthiaskrgr
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Jun 25, 2023
…mulacrum Expose `compiler-builtins-weak-intrinsics` feature for `-Zbuild-std` This was added in rust-lang/compiler-builtins#526 to force all compiler-builtins intrinsics to use weak linkage.
thomcc
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Aug 24, 2023
This was added in rust-lang/compiler-builtins#526 to force all compiler-builtins intrinsics to use weak linkage.
thomcc
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Aug 24, 2023
Expose `compiler-builtins-weak-intrinsics` feature for `-Zbuild-std` This was added in rust-lang/compiler-builtins#526 to force all compiler-builtins intrinsics to use weak linkage.
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When enabled, the weak-intrinsics feature will cause all intrinsics functions to be marked with weak linkage (i.e. `#[linkage = "weak"]) so that they can be replaced at link time by a stronger symbol.
This can be set to use C++ intrinsics from the compiler-rt library, as it will avoid Rust's implementation replacing the compiler-rt implementation as long as the compiler-rt symbols are linked as strong symbols. Typically this requires the compiler-rt library to be explicitly specified in the link command.
Addresses #525.